Abstract: An air flow system for a combination microwave and electric convection oven wherein a single motor drives two fans to generate a movement of air in an oven cavity and a movement of air in an electrical component compartment. The fan moving the air in the electrical component compartment is positioned between the fan moving the air in the oven cavity and the motor to act as a thermal barrier and to protect the motor from the heated air in the oven cavity. A portion of the air in the electrical component compartment may be diverted to the oven cavity and subsequently exhausted from the oven. Simultaneously, an electrical heater may be de-energized with the result that the air in the oven cavity is heated by resistive losses from components in the electrical component compartment. By combining this diverted air flow with a minimum of microwave energy, many types of foods may be effectively dehydrated in a substantially shorter than normal period of time.

Abstract: The invention relates to a power supply for microwave ovens and features a fail-safe door interlock switch system. Door interlock switch systems for microwave ovens are designed to stop or interrupt the flow of electrical energy to the magnetron tube upon the opening of the oven door to prevent the escape of microwave energy from the oven cavity through the open oven door. The interlock switch is normally in the power line and malfunctioning can occur in which the power line interlock switch does not open with the opening of the oven door either because of being welded closed or somehow stuck in a closed state. In this invention a fail-safe feature is provided for the interlock system. If a malfunction should cause the interlock power switch to remain closed upon the opening of the oven door, means are present which effectively break the power line to stop the flow of electrical energy to the magnetron tube.